Windows 7 loses network connection

modem : adsl
router : TP-LINK TL-WR1043NDS

from time to time, not regular, Win looses connection to the network.
Powering the router off and back on restores the connection.
My wife's computer connected to the same router (cable) is also disconnected.
The modem, which handles also the phone line, seems OK since I can still phone.

It probably isn't practical with the disconnects being irregular, but wiring one computer directly to the modem to see if they still occur would eliminate that, but instead of just rebooting the router, you could check to see if a power cycle improves things.

This is done by switching off the modem, router and all devices and disconnecting all cables for 2 - 5 minutes.

Reconnect the cables then switch just the modem on and wait for all the lights to come on and then do the same for the router and then switch just one machine back on and see how that goes.

It seems you are not alone... have a look at this post, especially the mention of "1.5.9 gargoyle firmware" upgrade by poster QD2. Gargoyle firmware is available from here and the 'supported routers' list is here.

I also experience occasional (several times a month) link loss with Win7 X64. I used to power cycle the router (Billion 7800N ADSL) until I noticed other devices on the network had not lost connectivity, just the Win7 machine. This may not work for you but I found that allowing Windows to repair the connection resolves the problem without interrupting other devices on the same router. Go to the Network and Sharing Center under the Control Panel when connection is lost and you will see a visual indication (an "x") of the link fault with a repair option. Cannot remember the precise details but it's self-explanatory when you see it. I should add that the machine that experiences the loss of connection is Ethernet connected while all other devices on the router are wireless connected. As to why the problem occurs in the first place, my impression is that it may be load-related but I have no hard evidence to back that up.

I also experience occasional (several times a month) link loss with Win7 X64. I used to power cycle the router (Billion 7800N ADSL) until I noticed other devices on the network had not lost connectivity, just the Win7 machine. This may not work for you but I found that allowing Windows to repair the connection resolves the problem without interrupting other devices on the same router. Go to the Network and Sharing Center under the Control Panel when connection is lost and you will see a visual indication (an "x") of the link fault with a repair option. Cannot remember the precise details but it's self-explanatory when you see it. I should add that the machine that experiences the loss of connection is Ethernet connected while all other devices on the router are wireless connected. As to why the problem occurs in the first place, my impression is that it may be load-related but I have no hard evidence to back that up.

May be worthwhile downloading the Ethernet driver and Event Viewer may have something recorded for it.

The Reliability history may also have something listed which is accessed from Start - type reliability - press Enter and click on any red crosses that you see for the date.

I noticed today that, when I have no connection to the Internet I can't ping the router or the modem.
More strange, although my computer has a fixed IP address (192.168.0.101) an "ipconfig /all" reveals an address of 192.168.0.104 !!!!
Powering off then on the router restores the connection and the address.

When DHCP starts playing up, sometimes factory resetting the router or re-flashing the firmware can resolve but after reading through one of the links in Rick's post (Post #3), that may not resolve and using the Gargoyle firmware which seems to have proven successful may be the way to go as Rick has suggested - but back up your router's current config first.

Probably a better option would be to RMA it if it's still under warranty.

When I've seen the need for having to power-reset a Router and/or Modem [either occasionally or frequently] it usually ended with the owner getting a new one. Do you get the same thing when plugging the Modem directly into the Ethernet port on the computer?

All the ISPs in my area use the 'Automatically detect' for the Connections, LAN Settings in Internet Options. My Router uses 192.168.1.1 as the Default Gateway but today my Win7 computer is 192.168.1.135, the computer never shows as being the same IP as the Default Gateway.

When I've seen the need for having to power-reset a Router and/or Modem [either occasionally or frequently] it usually ended with the owner getting a new one. Do you get the same thing when plugging the Modem directly into the Ethernet port on the computer?

All the ISPs in my area use the 'Automatically detect' for the Connections, LAN Settings in Internet Options. My Router uses 192.168.1.1 as the Default Gateway but today my Win7 computer is 192.168.1.135, the computer never shows as being the same IP as the Default Gateway.

When a computer has been set with a static IP address, the DHCP shouldn't assign it with a DHCP generated one which always starts from at least one up from the Default Gateway and is why an adapter that is DHCP assigned, is why it is never the same as the Default Gateway.